The present invention relates generally to an optical signal detector and, more particularly, to an optical signal detector that detects an optical signal from an optical source using a plurality of optical sensors having different wavelength selectivities, thereby determining the peak wavelength of the optical signal and measuring the power of an optical signal corresponding to the peak wavelength.
In general, in order to monitor wavelength-division-multiplexed multi-channel optical signals, the optical power, optical wavelength and Optical Signal to Noise Ratio (OSNR) of each optical signal channel must be measured.
Recently, with the introduction of Fiber To The Home (FTTH) networks, which are high-speed, high-capacity transmission networks, there is an urgent need for a method that can be easily used for the maintenance of the FTTH networks and that can accurately measure the wavelength and optical power of an optical source.
According to the IEEE standards, currently, FTTH employs signal wavelengths in bands of 1310 nm, 1490 nm and 1550 nm. It is necessary to measure the power of optical signals corresponding to the peak wavelength and other wavelengths of an optical source and maintain the performance of a network in a normal state using measured values at the time of laying optical fiber or repairing/recovering optical fiber in an HTTH network.
FIG. 1 is a block diagram showing a conventional optical signal detector.
As shown in this drawing, a conventional optical signal detector 100 is a device for measuring the wavelength and power of an optical signal incident from an optical source, and includes a primary optical detector 130 for detecting the power of an optical signal incident from an optical source and outputting a corresponding signal, one or more optical filters 111 to 11N (N=1, 2, 3, . . . ) for passing only optical signals, corresponding to respective preset transmissive wavelength bands, from the optical source, therethrough, one or more secondary optical detectors 121 to 12N located to correspond to the respective optical filters 111 to 11N and configured to output signals corresponding to respective powers of the optical signal passed through the optical filters 111 to 11N, a signal conversion unit 140 for converting signals, detected by the primary optical detector 130 and the secondary optical detectors 121 to 12N, into a form that can be processed, a wavelength determination unit 150 for determining the peak wavelength of the optical source based on the signals detected by the secondary optical detectors 121 to 12N, and a power measurement unit 160 for measuring the power of the optical signal corresponding to the peak wavelength based on the signal detected by the primary optical detector 130.
However, the conventional optical signal detector has a problem in that the optical filters and the secondary optical detectors are spaced apart from each other, and thus it is difficult to implement stable optical space arrangement therebetween, with the result that it is impossible to accurately measure the wavelength and power of an optical signal. Furthermore, there is a problem in that a complicated Gaussian approximate value must be calculated from discrete measured values. Furthermore, a problem arises in that the costs incurred by and mounting space required by the optical filters are considerable, so that the manufacturing costs thereof are high and the size thereof is large.